Food & Function Blog

Biological effects of milk peptides in relation to cardiovascular disease are reviewed in this article from Martha Phelan and David Kerins from Food for Health Ireland at University College Cork, Ireland.  The comprehensive review provides a valuable source of information to researchers. Heart disease and stroke are one of the leading causes of death and disability worldwide.  Bioactive peptides derived from milk proteins demonstrate many potential functional and physiological roles in relation to cardiovascular disease and as such are of great interest to the food industry. Due to the perception that food derived products have an acceptable risk profile they have the potential for widespread acceptance by the public. This article reviews many aspects of these dairy peptides such as bioavailability, inhibition of angiotensin converting enzyme, effect on platelet function and antithrombotic effects.

Interested in knowing more?  Read the full article here:

The potential role of milk-derived peptides in cardiovascular disease
Martha Phelan and David Kerins
Food Funct., 2011, Advance Article
DOI: 10.1039/C1FO10017C

Jianshe Chen and co-workers from the University of Leeds, UK, have developed a simple model device for routine investigation of in vitro gastric digestion.  Knowledge of food disintegration in the human stomach is essential for assessing the bioavailability of nutrients.  Studies in medicine, pharmacy and clinical nutrition have demonstrated that disintegration of food and drugs inside the stomach is a highly complicated process.  Food is broken down into small particulates and molecules as a result of both physical forces and chemical reactions; it is extremely difficult to mimic stomach conditions in vitro.

Although some very sophisticated in vitro digestion devices have been developed they are not suitable for routine use due to their complexity.  In this study, the UK Food Scientists describe a simple in vitro digestion device.  The device is housed in a water-jacketed glass vessel which has a constant flow around it to maintain body temperature.  A spherical Teflon probe of variable diameter can be inserted which is controlled by a texture analyser and moved up and down to simulate the kinetics of a food digestion process.  A schematic of the device is shown in the image to the right.

Under well controlled hydrodynamic flow and biochemical conditions this device can be used to determine key digestion parameters such as pH, food particle size, protein release, lipid release, cloudiness etc. Feasibility tests of the model device were conducted using roasted and non-roasted peanut particles; after digestion significant differences of surface microstructure were observed (see figure to left).  The study also showed that parameters such as food to gastric juice ratio, probe speed and pepsin concentration all influenced the kinetic process of gastric digestion and need to be well regulated in any in vitro digestion investigation.

This device has the advantages of easy control and operation and can be an ideal tool for routine in vitro gastric digestion studies.

Interested in knowing more?  Read the full text here.

Development of a simple model device for in vitro gastric digestion investigation
Jianshe Chen, Vishwajeet Gaikwad, Melvin Holmes, Brent Murray, Malcolm Povey, Ye Wang and Ying Zhang
Food Funct., 2011, Advance Article
DOI: 10.1039/C0FO00159G

A team from India has shown that an edible blue-green algae Spirulina laxissima can protect the liver against CCl₄ induced oxidative damage in rats.

Spirulina species have been used as food for thousands of years and many medicinal properties have been attributed to them such as weight and cholesterol reduction and radical-scavenging action.  Spirulina is also an important source of the blue photosynthetic pigment phycocyanin (PC), which has been described as a strong antioxidant and anti-inflammatory natural compound.  Carbon tetrachloride (CCl₄) is a well-known hepatotoxic agent. The changes associated with CCl₄-induced liver damage are similar to those of acute viral hepatitis and CCl₄-induced liver damage is a classic model used for the screening of hepatoprotective drugs.

The ethanol extract of Spirulina laxissima (EESL) was used in experiments as it was demonstrated to have the greatest antioxidant properties compared to methanol and water extracts.  In this study EESL was dosed an hour before CCl₄ and the treatments were administered to rats 3 times a week for 5 weeks.  A variety of markers were used to assess liver function after this period; protein and antioxidant levels in the liver as well as liver function marker enzymes. Treatment with CCl₄ resulted in liver damage in all parameters tested, but treatment with EESL before CCL₄ treatment reduced the hepatotoxic effects of CCl₄.

This study, by Gini C. Kuriakose and Muraleedhara G. Kurup, demonstrates the hepatoprotective and antioxidant properties of the ethanol extract of S. laxissima (EESL). The authors suggest that the hepatoprotective effect of EESL may be due to the presence of phycocyanin pigment however further studies are needed to identify and isolate the active principles of EESL.

Interested in knowing more?  Read the full article here!

Antioxidant and antihepatotoxic effect of Spirulina laxissima against carbon tetrachloride induced hepatotoxicity in rats
Gini C. Kuriakose and Muraleedhara G. Kurup
Food Funct., 2011, Advance Article
DOI: 10.1039/C0FO00163E

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A team from the Central Food Technological Research Institute in India has identified the expression pattern of carotenoid biosynthetic pathway genes during tomato ripening.  Their results may provide insight into devising gene-based strategies for enhancing carotenoid accumulation in tomato fruits.  This has significance because consumption of fruit and vegetables, especially tomatoes, has been linked with a reduced risk of cancer in epidemiological studies: evidence increasingly suggests that this is due to the antioxidant effect of carotenoids. 

The ripening of tomato fruit is a highly regulated process during which co-ordinated genetic and biochemical events take place leading to changes in fruit texture, aroma, colour and flavour.  One of the most important and noticeable changes during ripening is the change in pigmentation due to a massive accumulation of the bright red carotenoid lycopene.

In this study, Singh Negi and co-workers investigated the expression of carotenoid biosynthetic pathway genes and the lycopene content at different stages of maturity in tomato fruit.  The results revealed that there was an increase in the levels of upstream genes of the carotenoid biosynthetic pathway 5 days before lycopene content peaked.  Lycopene accumulation also coincided with the colour values at different stages of maturity. This complete gene expression analysis could inform strategies for enhancing the accumulation of lycopene in tomatoes, thus increasing their potential health benefits.

Interested in knowing more? Read the full article here!

Expression of carotenoid biosynthetic pathway genes and changes in carotenoids during ripening in tomato (Lycopersicon esculentum)
Kanakapura Krishnamurthy Namitha, Surya Narayana Archana and Pradeep Singh Negi
Food Funct., 2011, Advance Article
DOI: 10.1039/C0FO00169D

A team from The Netherlands have validated a set of normalization genes for quantitative RT-PCR in differentiated Caco-2 cells and used them to detect changes in gene expression upon exposure to apple, tomato, broccoli and mushroom.

Fruit and vegetables are considered a healthy food choice and many potential health promoting compounds have been identified.  However, fruit and vegetables are complex products with a wide variety of compounds; therefore, a tool is required which analyses the potential bioactivity of whole foods or food products rather than the mechanisms of a single bioactive compound.  This paper describes the development of such a tool by Robert Vreeburg and co-workers from the Wageningen University and Research centre.

Intestinal cells are exposed to food we consume and it has been shown that their functions can be modulated by food compounds. Furthermore, in vitro cell lines (such as the human, colon derived Caco-2 culture) can mimic these responses.  The most versatile readout for detecting responses of cells is to measure changes in mRNA abundance; this gives a snapshot of the gene expression of a cell.  Changes in mRNA are detected using a technique called quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) which requires a set of normalisation genes whose expression will not change upon exposure to food.

This study identifies a set of reference genes suitable for RT-qPCR use in food exposure studies with the intestinal-like Caco-2 cell line.  The reference genes are validated by exposing the Caco-2 cell line to homogenates of apple, tomato, broccoli and mushroom.  These food homogenates provoked gene expression changes in the cell line thus showing that natural food homogenates can exert effects in Caco-2 cells, and that the stability in expression of the reference genes is not due to a lack of response of the Caco-2 cells.

Interested in knowing more?  Read the full text for free here.

Normalization genes for quantitative RT-PCR in differentiated Caco-2 cells used for food exposure studies
Robert A. M. Vreeburg, Shanna Bastiaan-Net and Jurriaan J. Mes
Food Funct., 2011, Advance Article
DOI: 10.1039/C0FO00068J

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Green tea accounts for 20% of all tea consumed globally and it has long been associated with a reduced risk of cancer development.  It is generally agreed that much of the chemopreventitive effects of green tea are due to its catechin compounds; (–)-Epicatechin-3-gallate (ECG) and (–)-Epigallocatechin-3-gallate (EGCG).  These polyphenolic antioxidants have been widely studied and it has been shown that they inhibit the growth of various cancer cells in culture and demonstrate antitumor activity in in vivo models. 

Despite a large body of literature on the cancer-preventative mechanisms of both EGCG and ECG, review articles to date solely focus on EGCG.  Min-Hsiung Pan, Jen-Kun Lin and co-workers from Taiwan and the USA have now written an excellent review for Food & Function which provides a comprehensive overview of the anti-carcinogenic effects and molecular mechanisms of ECG.

To find out more read the full article ‘Multistage carcinogenesis process as molecular targets in cancer chemoprevention by epicatechin-3-gallate’ here.

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A team from The Pennsylvania State University have shown that one of the major polyphenols in green tea, (–)-Epigallocatechin-3-gallate (EGCG), increases the expression of genes related to fat oxidation.  EGCG has been show to prevent the development of obesity in rodent models and may also modulate body weight in humans.  Mechanisms accounting for this effect that have been demonstrated include a decrease of fat absorption in the small intestine and modulation of genes related to lipid metabolism in the liver, white adipose tissue and skeletal muscle; although in the latter tissue, comparatively little is known.

Joshua D. Lambert and co-workers investigated the expression of several genes related to lipid oxidation in the skeletal muscle of high fat-fed mice.  They also compared these changes to observed effects on physiological markers of obesity, type II diabetes and obesity-related fatty liver disease (ORLFD).   

Results showed that high fat-fed mice treated with EGCG had reduced body weight gain and final body weight compared to high fat-fed controls.  EGCG treatment also decreased fasting blood glucose, plasma insulin, insulin resistance and markers of ORFLD.  The expression of mRNA from genes relating to mitochondrial fatty acid oxidation was increased as was the levels of fat in the excretion.  Taken together, these results suggest that EGCG modulates body weight gain by modulating both lipid metabolism and fat absorption.

So, it may be that drinking green tea could help with those new years resolutions to shed a few pounds; however, you’ll have to drink a lot as the levels used in this study correspond to a human consumption of approximately 10 cups a day!

Interested in knowing more? Read the full text here.

(−)-Epigallocatechin-3-gallate increases the expression of genes related to fat oxidation in the skeletal muscle of high fat-fed mice
Sudathip Sae-tan, Kimberly A. Grove, Mary J. Kennett and Joshua D. Lambert

A team from the University of Lisbon in Portugal has demonstrated, in vivo, the effects of a herbal tea (Lamiaceae) which may have beneficial effects on Alzheimer’s Disease.

Leaves of Plectranthus barbatus (Lamiaceae) are used to make herbal teas and as a traditional remedy for a wide range of diseases, recently they have been shown, in vitro, to possess anti-oxidant and anti-acetylcholinesterase activity.  Acetylcholinesterase (AChE) inhibition is the most effective pharmacotherapy for the symptomatic treatment of Alzheimer’s disease.  The active component responsible from Lamiaceae has been identified as rosmarinic acid, however, effects of this compound in the body are dependent on its metabolism.  It is these metabolites and the places they reach that will exert a physiological effect.  In this study Serralheiro and colleagues set out to determine, in vivo, if Lamiaceae herbal tea and pure rosmarinic acid could pass the digestive tract and keep some of their functions, particularly in the brain given the potential Alzheimer’s benefits.

Lamiaceae herbal tea and pure rosmarinic acid were administered to rats intragastrically and intraperitoneally.  The resulting metabolites in the plasma and brain were studied as was brain AChE activity.  Upon intragastric administration of tea, only traces of metabolites were found in plasma and none in the brain.  However, a decrease in brain AChE activity of about 10% was detected.  When pure rosmarinic acid was administered intragastrically it was detected in the plasma.  Upon intraperitoneal administration of tea all metabolites were detected in plasma and rosmarinic acid detected in the brain; resulting in a decrease in brain AChE of about three times that of intragastric administration.

Taken together the results suggest that the rosmarinic acid present in herbal teas may cross the intestinal barrier as well as the blood brain barrier.  It has also been shown that in the brain rosmarinic acid inhibits AChE activity.

Read the full text for free here!

Function of Plectranthus barbatus herbal tea as neuronal acetylcholinesterase inhibitor 
Pedro L. V. Falé, Paulo J. Amorim Madeira, M. Helena Florêncio, Lia Ascensão and Maria Luísa M. Serralheiro
Food Funct., 2011, Advance Article
DOI: 10.1039/C0FO00070A, Paper

‘Dibenzoylmethanes (DBMs), isolated from liquorice, have excellent anti-inflammatory and anti-cancer effects,’ claim scientists in Taiwan and the US.

DBMs are β-diketone structural analogues of curcumin and have an aspirin-like skeleton. Curcumin and aspirin are known to possess anti-inflammatory and chemopreventive effects through suppression of COX-2 gene expression.  Due to the structural similarities between DBM and curcumin and aspirin, Chuan-Chuan Lin and co-workers tested the anti-inflammatory and anti-cancer effects of DBMs. They found DBMs to have the potential to substitute for aspirin in therapeutic anti-inflammation treatment. In addition, they also noted the DBMs activities as an anticancer agent.

The team from the China University of Science and Technology and the State University of New Jersey in the US believes that DMBs acts by inhibiting the COX-2 enzyme. It is known that expression of COX-2 is associated with chronic inflammation and epithelial carcinogenesis. The team used the tumour promoting agent 2-O-Tetradecanoylphorbol-13-acetate (TPA), which induces COX-2 expression causing tumours and ear edema in the skin of mice. Lin et al. found that DBMs inhibited TPA-induced skin tumours significantly and that some of the DMB compounds possessed superior anti-inflammatory properties than aspirin. 

Read more about this paper here:
Inhibitory effects of 1,3-bis-(2-substituted-phenyl)-propane-1,3-dione, β-diketone structural analogues of curcumin, on chemical-induced tumor promotion and inflammation in mouse skin
Chuan-Chuan Lin, Yue Liu, Chi-Tang Ho and Mou-Tuan Huang
Food Funct., 2011, Advance Article
DOI: 10.1039/C0FO00098A, Paper